The present invention relates to an optoelectronic device and an information apparatus using the optoelectronic device. Furthermore, the present invention relates to a data transmission system for controlling the information apparatus which includes a plurality of sensors and to transmit outputs of the sensors.
The above-mentioned optoelectronic device includes for example, a light-receptacle device, a luminous device, a solid-state relay, a photo-interrupter, and a photo-coupler for sensing an object without physical contact, a photo-coupler for inputting or outputting a signal. The above-mentioned information apparatus includes, for example a printer, a facsimile, a copying machine, and a programmable controller. The above-mentioned data transmission system represents a system which uses an apparatus such as a copying machine, a video tape recorder, an audio equipment, a domestic electric product, a car-equipped electric product, an electric music instrument, or an industrial apparatus.
A photo-interrupter which is arranged to have a luminous element 11, a light-receptacle element 12, an amplifier 13 and a transistor 14 is shown in FIG. 1. In operation the luminous element 11 is made luminous by flowing current therethrough. The photo-interrupter determines whether or not the light-receptacle element 12 receives a larger amount of light than a threshold light amount and outputs a high signal or a low signal depending on a result of the determination.
A copying machine which uses a large number of photo-interrupters mounted thereon for increasing its functions is shown in FIG. 2. For supplying a sensing signal from the photo-interrupters, the known copying machine is required to provide a plurality of signal lines 17 inside of a control unit 15 between the control unit 15 and the plurality of photo-interrupters. As a consequence, the inside wiring arrangement is very intricate, thereby inhibiting a reduction of the apparatus size.
A light-receptacle device is shown in FIG. 3. The light-receptacle device is arranged to have a photo-diode 18, an amplifying circuit 19 and a waveform shaping circuit 20. The light-receptacle device supplies a high signal or a low signal based on a result of the determination whether or not the light is applied to the photo-diode 18.
An information apparatus may use a larger number of light-receptacle devices in accordance with an increased number of the sensors provided in the apparatus. As shown in FIG. 4, the information apparatus is required to provide the corresponding number of transmission lines 22 to that of the light-receptacle devices for transmitting data between a plurality of the light-receptacle devices and one control unit (CPU) 21. It results in making the internal wiring arrangement more intricate, thereby the apparatus becomes bulkier.
This arrangement requires more power consumption, because it is necessary to provide the same number of the transmission lines connected between the CPU 21 and the light-receptacle devices as the number of the light-receptacle devices as stated above and the power for a light sensor circuit has to be turned on.
A photo-coupler shown in FIG. 5 may be used for an information apparatus, for example, a programmable controller. Several signal lines from input photo-couplers (input 1 to N) and output photo-couplers (output 1 to N) are connected in parallel with an external control device (microcomputer) C.
With an increase of a number of the photo-couplers being used, the overall length of patterns led inside of the substrate and lead wires installed inside of the device becomes considerably long, it results in occupying a considerable area and enlarging the size of the apparatus, overall.
A luminous device, which is shown in FIG. 6 is arranged to have a light-emitting diode 23 and an oscillation circuit 24 for driving the light-emitting diode 23. The luminous device operates to emit a pulsed ray of light constantly.
Recent information apparatus use a larger number of luminous elements with an increase of the sensors used in the information apparatus and having an arrangement as shown in FIG. 6. It is necessary to provide the corresponding number of transmission lines as that of the luminous devices in order to transmit data between those luminous devices and one central processing unit (CPU) 25 as shown in FIG. 7. As a consequence, wirings inside of the apparatus will be more intricate, thereby the apparatus becomes bulkier. Further, this arrangement requires more power consumption as mentioned above, because it is necessary to provide the corresponding number of transmission lines as that of the luminous devices and the power source for keeping the oscillation circuit 24 constantly.
A photo-triac used in a solid-state relay S as shown in FIG. 8. The solid-state relay S is arranged to have a luminous element (light-emitting diode) 26, a light-receptacle element 27, a photo-triac 28 and a main triac for power 29. The luminous element 26 serves to emit light to the light-receptacle element 27. The photo-triac 28 serves to conduct alternating ac in response to the light received in the light-receptacle element 27. The main triac for power 29 serves to switch on and off the external unit in a case that the photo-triac 28 becomes conductive. The alternating current is controlled on and off depending on the on-state and off-state of the luminous element 26.
In recent days, a copying machine utilizes a large number of solid-state relays in order to keep its function higher.
In a case that a plurality of solid-state relays are connected to a control unit 30 inside of the copying machine, as shown in FIG. 9, it is necessary to provide a plurality of signal lines 31 (lead wires) between those solid-state relays S and the control unit 30 for various purposes, resulting in making an arrangement of the internal wiring more intricate, thereby the copying machine becomes bulkier.
Another photo-interrupter is shown in FIG. 10. This photo-interrupter includes a luminous element 32, a light-receptacle element 33, an operational amplifier 34 and a transistor 35.
When the luminous element 32 is made luminous by flowing current therethrough, the light-receptacle element 33 serves to generate current depending on the quantity of the received light. Then, the operational amplifier 34 serves to amplify the generated current and to determine whether or not the amplified current is equal to or larger than a threshold quantity of light. The transistor 35 is arranged to supply a high or a low signal depending on a result of the above-determination.
In recent days, a copying machine utilizes a large number of the above-mentioned photo-interrupters in order to keep its function higher. For a certain type of copying machine, several hundreds photo-interrupters may be used.
As shown in FIG. 11, it is necessary to connect a plurality of signal lines 37 in parallel between the control unit 36 and those photo-interrupters for supplying sensing states of the photo-interrupters 38A to 38L to the control unit 36. As a result, the internal wiring arrangement will be more intricate, thereby the copying machine becomes bulkier.
A data transmission system is shown in FIG. 12. This data transmission system is arranged to have photo-interrupters 39, each of which is connected to a control unit (microcomputer) 40, a luminous element (light-emitting diode) 41, a current-limiting resistor 42, a light-receptacle element (photo-transistor) 43.
Output resistors 44 are connected to the photo-transistors 43, and output wires 45 are led from the output resistors 44.
Those output wires 45 are connected to the microcomputer 40. Since an object partially screens the light applied from the light-emitting diode 41 to the photo-transistor 43, the photo-interrupters 39 serve to change current flowing through the output resistors 44, thereby changing the voltages on the output wires 45.
With recent enhancement of functions of the apparatus, the photo-interrupter used in the data transmission system are increased in number. It results in increasing the internal wires in number and making the internal wiring arrangement more intricate.